Chuck with vibration damping

ABSTRACT

A tool chuck for clamping a tool in a machine tool, having a base body and a sleeve part protruding therefrom, which sleeve part forms a tool holder for fixing a tool shaft in a frictional, nonpositive fashion; a cavity in which a vibration damping component is accommodated is provided in the tool chuck.

FIELD OF THE INVENTION

The invention relates to a tool chuck for a tool that rotates around anaxis of rotation during operation, in particular a drilling, milling,reaming, or grinding tool. The tool chuck can be composed of one or moreparts. Typically, at its end normally oriented toward the machine tool,it has a coupling section for coupling to the machine tool and at itsend oriented away from the machine tool, it has a sleeve part forchucking a tool shaft.

BACKGROUND OF THE INVENTION

Not least when such tool chucks are used to hold tools in the form ofmilling cutters that rotate at a high speed in which the number ofcutting edges currently in contact with the material to be machinedfluctuates constantly by nature, the problem, arises that the sleevepart of such tool chucks is excited into executing undesirablevibrations.

In particular, bending vibrations occur in the sleeve part due to thebending of the sleeve part around a bending axis essentiallyperpendicular to the axis of rotation. Sometimes torsional vibrationsalso occur due to a resilient flexing of the sleeve part around its axisof rotation. In practice, mixed forms of these vibrations also occur,but often the radial portion predominates. Any vibrations potentiallylimit the machining precision that can be achieved with the tool, It isnot unusual for such vibrations to also have a negative impact on theservice life of tool cutting edges.

In the prior art, there has been no shortage of attempts to design toolchucks with a reduced tendency to vibrate by providing the tool chuckwith integrated, long mass elements whose mass or natural vibrationbehavior improved the vibration behavior of the tool chuck as a whole.But since the prior assumption was that the mass elements can only besufficiently effective if they have a substantial dimension in thedirection of the axis of rotation, the previously known vibration-dampedtool chucks are distinguished by the fact that they have a substantialoverall length. This is cumbersome for a not insignificant number ofapplications.

By contrast, the object of the invention is to provide compact toolchucks that have only a reduced tendency to vibrate.

SUMMARY OF THE INVENTION

Consequently, what is described herein is a tool chuck for clamping atool in a machine tool, having a base body and a sleeve part protrudingtherefrom, which sleeve part forms a tool holder for fixing a tool shaftin a frictional, nonpositive fashion, In this case, a cavity is providedin the tool chuck, in which a vibration-damping component is situated,which is preferably an additional component that is embodied as separatefrom the base body and the sleeve part.

Preferably, the cavity begins in the vicinity of the transition from thebase body to the sleeve part and extends from there along the axis ofrotation in the direction toward the tool holder.

Ideally, the cavity has a length along the axis of rotation that is lessthan ⅖ and preferably less than ⅕ the length of the tool holder in thisdirection. Contrary to what was taught in the prior art, the lengths—inthe direction of the axis of rotation—of the cavity and of thevibration-reducing component contained therein are kept short. At thesame time, the cavity and therefore also the spatial localization of thevibration-reducing component contained therein are concentrated on thevicinity of the transition from the base body into the sleeve part.

This particular embodiment departs from the previous concept ofpositioning the vibration-reducing component also in a region remotefrom the transition between the base body and the sleeve part and givingit a substantial length and thus a considerable mass in order to thusproduce the best possible effect. Surprisingly, it has turned out herethat even a vibration-reducing component that is embodied as relativelydelicate—as long as it is positioned in the vicinity of the transitionfrom the base body to the sleeve part—produces a considerable effect,which was not expected.

This is particularly true when the sleeve part is embodied verycompactly in the direction of the axis of rotation in that the length ofthe sleeve part is essentially limited to the length of the tool holder(including its outlet, which serves to adjust the length of the tool andwhich is included under the term “tool holder” in this description).This is the case when the length of the tool holder makes up more than¾—and better still more than ⅘—of the overall length of the sleeve part.

In this connection, it has turned out to be particularly effective toposition the cavity so that it directly adjoins the region of the changein diameter at which the sleeve part transitions into the base body oreven so that it lies within this region along with thevibration-reducing component that is inserted into it so that the changein diameter—viewed in the direction of the axis of rotation—occurs atthe level of the circumference wall that delimits the cavity.

Advantageously, the cavity does not, extend all the way through thesecuring flange and therefore does not reach into the coupling section.

Advantageously, the cavity is encompassed in the circumference directionby a joint between the base body and the sleeve part, which ispreferably embodied in the form of a welded seam. The base body and thesleeve part are thus welded together in a region that constitutes thecircumferential boundary of said cavity. Alternatively, a glue joint canalso be provided, but a weld is preferable.

In a preferred embodiment, the vibration-reducing component is embodiedas a disc and in particular as an annular disc with a central opening.Such a central opening is used as a passage for the conduit that extendsthrough the tool chuck, via which the tool can be supplied with coolinglubricant. Advantageously, the maximum dimension B_(max) of the discparallel to the axis of rotation is less than the maximum diameterD_(max) of the disc, preferably in accordance with the equationB_(max)/D_(max)≦2 and ideally, in accordance with the equationB_(max)/D_(max)≦3.

Preferably, the disc is composed of metal, in particular a heavy metalor a metal and in particular, a material that contains heavy metal. Inthe context of the invention, a “heavy metal” is understood to mean anymetal that has a specific weight that is at least 10% higher than thatof unalloyed steel. Copper is a heavy metal that is predestined for usein the context of the invention. Copper is available for a reasonableprice, easy to handle, and when used in the manner according to theinvention, has noticeably better damping properties than steel.Tungsten, for example, is also very suitable because of its extremelyhigh weight; it is also possible to use lead.

It has also turned out to be a very advantageous alternative to producethe disc out of a metal alloy with a particularly powerful vibrationdamping action, as is currently offered by the company Les Bronzesd'Industrie: 26 rue de la République, 57360 Amnéville, France under thebrand name EXTUIM® AM.

An advantageous modification of the invention is comprised in that thedisc rests with at least one of its circumference surfaces directlyagainst a corresponding circumference surface of the sleeve part and/orbase body. As a result, it is very easy to keep the disc in a centralposition relative to the axis of rotation, while it acts on the basebody and the sleeve part primarily with its end faces so that areduction in undesirable vibrations occurs.

The action of the disc can be limited to the fact that solely due to itsmass, it exerts a positive influence on the vibration behavior of thesleeve part.

Preferably, the disc is employed to subject the sleeve part to aprestressing force acting in the direction of the axis of rotation. Forthis purpose, the maximum dimension B_(max) of the disc is selected sothat the end faces of the sleeve part and base body do not rest againsteach other when these two parts are assembled with the disc interposedbetween them. Then the assembly is compressed with a press so that theend faces of the sleeve part and base body come closer to each otherthrough an elastic deformation of the disc, whereupon they are welded toone another. The elastically compressed disc produces a permanentprestressing force in the sleeve part, which exerts a positive influenceon its vibration behavior.

An advantageous modification of the invention to be used as analternative is comprised in the fact that the disc rests with acircumference surface via an intermediate layer composed of plasticand/or elastomer against a corresponding circumference surface of thesleeve part and/or base body such that with proper operation, the discis able to execute relative movements in the radial direction inrelation to the sleeve part and the base body. In this way, the disc canin turn be excited to execute vibrations in the radial direction thatoverlap with the undesirable vibrations executed by the sleeve part.Preferably, the disc in this case, with its end faces betweencorresponding end faces of the sleeve part and the base body, is eithernot clamped or not clamped so powerfully as to produce a significantrestriction of its mobility in the radial direction. Instead, the disccan be excited to execute vibrations in the radial direction. Thesevibrations overlap with the vibrations of the sleeve part, thusadvantageously influencing the vibration behavior of the sleeve partbecause an at least partial cancellation of the undesirable vibrationsof the sleeve part occurs. The disc functions as a vibration damper, soto speak.

In another preferred embodiment, the vibration-reducing component isheld inside the tool chuck and equipped in such a way that it isintrinsically excited to execute vibrations during operation—so thatduring operation, a part of the spring element that protrudes freelyinto the cavity of the tool chuck begins to vibrate relative to the partof the spring element that is fastened to the tool chuck. In this way aswell, vibrations of the vibration-reducing component can be produced,which in turn overlap with the undesirable vibrations of the sleeve partso that the latter are at least partially canceled out. This design istherefore another variant of a vibration damper.

In order to implement the above-described vibration damper, it isparticularly advantageous if the sleeve part, on its end face orientedtoward the base body, has a first annular flange for connection to thebase body and a second flange situated concentrically inside the firstannular flange that does not come into contact with the base body evenin the completely assembled state. A section of the spring element isaffixed to the latter flange, while a section of the spring elementoriented away from the fastening point extends into the cavity of thetool chuck as a result of which, this section of the spring elementopposite from the part of the spring section that is affixed to thesleeve part can be excited to execute vibrations.

The vibration-reducing component can be embodied so that thepreponderance of its spring deflection that is used according to theinvention is not produced by the elasticity that is also inherent in anyelement composed of solid material, but rather by the spatial embodimentof the spring element that achieves a significant enlargement of thespring deflection as compared to that of a corresponding solid element.

Advantageously, the spring element is composed of at least two, ideallyat least three, rings situated one inside the other, that are connectedto one another by means of bridge pieces that extend essentially in theradial direction in this exemplary embodiment.

Through the design of the spring element, it is possible to exert asubstantial influence on the natural vibration behavior and thereforedamping behavior of the spring element

In an alternative embodiment, the base body and the sleeve part areassembled with frictional, nonpositive engagement not directly, but withthe interposition of a material layer that provides a damping action andconstitutes the connection between the base body and the sleeve part.This has an advantageous effect on the vibration behavior of the sleevepart and the vibrations of the sleeve part are transmitted unhindered tothe spindle of the machine tool.

The gap, which is situated between the sleeve part and base and isfilled with the damping material layer, is preferably embodied aswedge-shaped or conical so that the sleeve part and base body arepressed into each other in a centering fashion by compressive forcesacting in the direction of the axis of rotation.

For this embodiment, it is particularly advantageous to equip the endfaces of the sleeve part and/or base body oriented toward the gap withundercuts into which the damping material layer can penetrate in orderto produce a form-fitting engagement. This provides for a particularlysecure anchoring of the damping material layer to the base body and/orthe sleeve part.

In lieu of actual undercuts, it is also optionally possible to merelyprovide a profiling of the corresponding end face.

Other potential embodiments, modes of operation, and advantages of theinvention ensue from the following description of the various exemplaryembodiments of the invention in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a tool chuck of a first exemplary embodiment of theinvention in a sectional view along the axis of rotation R.

FIG. 2 shows a perspective side view of the tool chuck shown in FIG. 1.

FIG. 3 shows a tool chuck of a second exemplary embodiment of theinvention in a sectional view along the axis of rotation R.

FIG. 4 shows a section through the tool chuck shown in FIG. 3 along thesection line A-A.

FIG. 5 shows a perspective side view of the tool chuck shown in FIGS. 3and 4.

FIG. 5a shows a first variant of the exemplary embodiment described inconnection with FIGS. 3 through 5.

FIG. 5b shows an enlarged detail from FIG. 5 a.

FIG. 5c shows a possible modification of the first variant shown in FIG.5a and 5 b.

FIG. 5d shows a second variant of the exemplary embodiment described inconnection with FIGS. 3 through 5.

FIG. 5e shows an enlarged detail from FIG. 5 c.

FIG. 6 shows a tool chuck of a third exemplary embodiment of theinvention in a sectional view along the axis of rotation R.

FIG. 7 shows the third exemplary embodiment according to FIG. 6 in asectional view along the section line B-B.

FIG. 8a shows an enlarged detail of the region labeled with the letter Xin FIG. 7.

FIG. 8b shows an enlarged detail of the region labeled with the lettersXX in FIG. 6.

FIG. 9 shows a perspective side view of the tool chuck shown in FIGS. 6through 8.

FIG. 10 shows a tool chuck of a fourth exemplary embodiment of theinvention in a sectional view along the axis of rotation R.

FIG. 11 shows a section through the tool chuck shown in FIG. 10 alongthe section line C-C.

FIG. 12 shows a perspective side view of the tool chuck shown in FIGS.10 and 11.

DETAILED DESCRIPTION OF TEE PREFERRED EMBODIMENTS

FIG. 1 shows an entire tool chuck 1 according to the first exemplaryembodiment. This tool chuck 1 is composed of a base body 2 and a sleevepart 3 protruding therefrom. A tool holder 4 is embodied inside thesleeve part 3.

In this case, the tool chuck is embodied as a so-called shrink fitchuck. The inner diameter of the tool holder 4 embodied in the sleevepart 3 is somewhat smaller than the outer diameter of the tool shaft,not shown, so that the sleeve part 3 holds the tool shaft firmly in asnug fit once the sleeve part 3 has cooled again after insertion of thetool shaft. Because of the details it contains relating to this,reference is hereby made to the applicant's European Patent EP 1 804900, the full content of which is incorporated by reference into thepresent description.

The use of the invention is particularly advantageous for so-calledshrink fit chucks that are usually composed of a solid sleeve part 3that does not have any significant discontinuities. It should be statedat the outset, though, that the protection claimed for the invention isnot restricted to chucks of this kind, but can instead also be used, forexample, for chucks of the Weldon type, whistle-notch type, or collettype.

As is clearly evident from FIG. 1, the base body 2 has a couplingsection 5. This section is used to couple the unit, which is composed ofthe tool chuck 1 and the tool it holds, to a machine tool. The couplingsection 5 in this case is embodied in the form of a steeply conicalcoupling shaft, which is advantageous, but the protection is not limitedto this, also see the other exemplary embodiments shown in the figures,some of which show a hollow shaft coupling (HSK coupling). The couplingshaft therefore makes no contribution as such to the production ofvibrations since it behaves in an extraordinarily rigid fashion notleast because it is clamped into the spindle of the machine tool.

Furthermore, the base body 2 generally has a securing flange 6 to whicha handling system, regardless of its embodiment, can be attached inorder to permit handling of the tool chuck 1 during the automatic toolchange. Because of its large diameter, the securing flange itself doesnot tend to contribute to the production of vibrations.

After the securing flange 6, the base body 2 usually transitions intothe sleeve part 3 with a change in diameter.

As shown in FIG. 1, a cavity begins in the vicinity of this transitionbetween the base body 2 and the sleeve part 3 and extends in thedirection of the axis of rotation R to the tool holder 4. The cavity inthis case can protrude a certain distance farther into the region of thesecuring flange 6, but does not reach into the coupling section 5. Themaximum diameter of the cavity is greater than the maximum diameter ofthe tool holder or the conduit for supplying the tool with coolinglubricant. This cavity, which is jointly formed by the base body 2 andthe sleeve part 3, encloses a vibration-reducing component 7, which inthis case is embodied as a separate component. The cavity is embodied asconspicuously short in the direction of the axis of rotation R; in thiscase, its length L_(K) is less than 1/9 the length L_(W) of the toolholder. The vibration-reducing component 7 essentially fills the cavitycompletely so that the same is true for the length of thevibration-reducing component viewed in the direction of the axis ofrotation.

FIG. 1 also makes it very apparent that the overall length L_(HG) of thesleeve part is kept to the absolute minimum. The length L_(W) of thetool holder embodied in the sleeve part makes up more than ⅘ of theoverall length L_(HG) of the sleeve part.

The vibration-reducing component 7 in this case is embodied as a ringmade of heavy metal and/or as a ring made of a metal with a particularlypowerful vibration damping action, as is currently offered by thecompany Les Bronzes d'Industrie, 26 rue de la République, 57360Amnéville, France under the brand name EXIUM® AM.

FIG. 1 clearly shows that the maximum dimension B_(max) of the annulardisc or ring parallel to the axis of rotation is less than the maximumdiameter D_(max) of the ring by a factor of more than 4. In the regionof its center, this ring has an opening 8 that contributes to thecreation of a conduit extending through the base body 2 and sleeve part3 and reaching into the region of the tool holder 4, via which a supplyof coolant, for example, can be provided. If such a conduit is notneeded, then the ring can also be embodied as a solid disc, which is notshown in the drawings.

The ring is placed in the cavity without the insertion of an elasticintermediate layer. On its outer circumference, it rests directlyagainst the inner circumference of the sleeve part 3 and/or base body 2and is held in a centered position in relation to the axis of rotationR. In this case, the cavity containing the ring is dimensioned so thatthe end faces of the ring rest with a particular prestressing forceagainst the corresponding end faces of the cavity the ring is held inthe cavity in clamped fashion and thus imparts a prestressing force toat least some regions of the sleeve part 3, which exerts a positiveeffect on the vibration behavior of the sleeve part.

The above-mentioned prestressing force, however, is not the only effectthat can be taken advantage of when using such a ring.

On the contrary, the vibration-reducing component 7 in the form of thering can also or instead exert a positive influence in that in thecourse of the radial vibrations or “walking” movement of the rotatingsleeve part 3, the ring is compressed and at least partially releasedagain in quick succession and thus produces a damping effect. Not leastwith regard to this effect, it can be advantageous to provide the ringwith one or more local slots (not shown in the drawings) that promotethis effect.

in the exemplary embodiment shown here, the base body 2 and the sleevepart 3 originally constituted two separate components, which have beenwelded to each other in a subsequent step—but this is not the onlymanufacturing option; see below for more details.

If this advantageous manufacturing option is selected, then it isadvantageous that each of these components, in its imaginary end facefor contacting the respective other component, has a turned groove sothat these two components, once they are connected by the welded seam 9,combine to form the intrinsically closed cavity, which accommodates thevibration-reducing component 7 in the form of a ring. The intersticebetween the base body 2 and the sleeve part 3, which may possibly havedisappeared as a result of the subsequent welding, therefore spans aplane that touches or intersects the cavity. As a result, thevibration-reducing component 7 is situated precisely at the transitionbetween the base body 2 and the sleeve pan 3. In this case, theprestressing force with which the vibration-reducing component 7 restswith its end faces against the corresponding end faces of the base body2 and sleeve pan 3 can be conveniently set by pressing the base body 2and sleeve part 3 against each other with corresponding force as theyare being welded. Naturally, through an appropriate selection of thewelding parameters, care is taken to prevent the root of the molten massfrom directly reaching the vibration-reducing component 7 during thewelding because the melting of the vibration-reducing component 7 couldreduce the quality of the welded seam.

For the sake of completeness, it should be noted that the exemplaryembodiment can also be modified in that only the sleeve pan 3 or onlythe base body 2 has a turned groove or an arbitrarily produced recessthat serves to (almost completely) accommodate the vibration-reducingcomponent 7 in the form of a ring.

As indicated above, the welding of a separately produced base body 2 toa sleeve pan 3 is not the only way to produce a tool holder according tothe invention. Instead, modem technologies such as laser sintering makeit possible to produce the tool holder in one piece and thus to enclosethe vibration-reducing component 7, which in this case is also producedfrom a different material, in the position shown in FIG. 1 for thewelded design.

FIGS. 3 through 5 show a second exemplary embodiment of the invention.

Statements made above with regard to the first exemplary embodiment alsoapply correspondingly to this exemplary embodiment because the twoexemplary embodiments are identical with the exception of thedifferences described below.

As shown in FIG. 3, in this exemplary embodiment as well, a cavitybegins in the vicinity of this transition between the base body 2 andthe sleeve part 3; this cavity extends in the direction of the axis ofrotation R to the tool holder 4 and protrudes a certain distance fartherinto the region of the securing flange 6, but does not reach into thecoupling section 5.

Here, too, the maximum diameter of the cavity is greater than themaximum diameter of the tool holder or of the conduit for supplying thetool with cooling lubricant.

This cavity, which is jointly formed by the base body 2 and the sleevepart 3, once again encloses an additional vibration-reducing component7.

In this exemplary embodiment as well, the cavity is embodied asconspicuously short in the direction of the longitudinal axis; itslength L_(K) here is less than ⅕ the length L_(W) of the tool holder.The vibration-reducing component 7 essentially fills the cavitycompletely so that the same is true for the length of thevibration-reducing component viewed in the direction of the axis ofrotation.

In this exemplary embodiment as well, the vibration-reducing component 7is composed of a ring, which is preferably composed of a heavy metaland/or the particularly vibration-damping metal mentioned above.

Unlike in the first exemplary embodiment, however, this ring does notrest with its circumference surface directly against a correspondingcircumference surface of the sleeve part 3 and or the base body 2.Instead, between the circumference surface of the ring and thecorresponding circumference surface of the sleeve part 3 and/or basebody 2, there is a layer that is referred to here as the elastic layer10 and is composed of a preferably flexible plastic or an elastomermaterial. The layer is preferably embodied as annular and ideally, iskept quite thin, with a thickness of only 0.5 mm to 3 mm measured in theradial direction. The purpose of the layer is to permit the ring to movein the radial direction; in the material selection and positioning ofthe above-mentioned elastic material, care is taken to make sure not toimpede its elasticity or compressibility, for example through theinadvertent occurrence of a disadvantageous hydrostatic stress state inthe elastic material.

Preferably, the end faces of the ring are not provided with a layer ofthe above-mentioned flexible plastic or elastomer material. In thisexemplary embodiment, the end faces of the ring either do not restdirectly against the corresponding end faces of the base body 2 and thesleeve part 3 or do not rest against them with a perceptibleprestressing force or rest against them with less than a limitedprestressing force, which ensures that the ring can move in the radialdirection, producing corresponding, friction forces that can likewisehave a damping effect.

In a design of this kind, the ring tends to act as a vibration damperrelative to the radial vibrations occurring in the sleeve part 3, inother words, the ring has the tendency to execute counter-vibrationsthat at least partially interfere with the radial vibrations occurringin the sleeve part 3 and thus at least reduce the undesirable radialvibrations of the sleeve part 3.

If the ring is to act as a vibration damper of this kind, then its massmust not be too low. Because of this, in this second exemplaryembodiment, the ring, as can be seen quite well by comparing FIGS. 3 and1, is preferably embodied as wider in the direction of the axis ofrotation of the tool chuck than the corresponding ring in the firstexemplary embodiment. FIG. 3 clearly shows that the maximum dimensionB_(max) of the annular disc or ring parallel to the axis of rotation is,however, still smaller than the maximum diameter of the ring by a factorof more than 2.5.

FIGS. 5a and 5b show a first variant of the above-explained secondexemplary embodiment; all of the statements made above in connectionwith the second exemplary embodiment apply here as well, provided thatnothing to the contrary is stated in the following explanation of thethings that have been modified.

In this case, ins both the radial direction and the direction of theaxis of rotation R, the cavity is embodied as larger than thevibration-reducing component 7 that it accommodates, which in this caseis embodied in the form of a ring that tends to act as a vibrationdamper. Because of this, there is no contact anywhere between the ringand the boundary walls of the cavity.

Between the circumference surface of the ring and the correspondingcircumference surface of the sleeve part 3 and/or base body 2, there isa layer that in this case is also referred to as the elastic layer 10.Via this layer, the circumference of the ring indirectly contacts theinner circumference of the cavity, while the end faces of the ringpreferably have complete freedom of motion and, in the neutral position,are preferably spaced apart from the end-face boundary walls of thecavity by a distance of at least 5/10 mm or, better still, by a distanceof at least 10/10 mm,

The above-mentioned layer is preferably embodied so that in its neutralposition, the ring, even on its outer circumference, maintains adistance of at least 5/10 mm and ideally at most 4/10 mm from thecircumference wall of the cavity since otherwise, it does not haveenough freedom to execute the required vibrations or its tendency tovibrate becomes too high.

The purpose of this layer is to permit a more than merely insignificantmovement of the ring in an essentially radial direction and it isembodied accordingly.

This layer is preferably comprised of an annular element that is hollowon the inside and is therefore correspondingly compressible in theradial direction, see FIG. 5b . An element that is hollow on the insideand is preferably closed in the circumference direction is ideal, butthis is not the only conceivable embodiment. Instead, for example, it isalso possible to use an element that is preferably closed in thecircumference direction and has one or more local recesses on the insideand/or on the outer circumference that produce, a correspondingcompressibility, see FIG. 5c . Finally, as a further alternative, it isconceivable to use an element that will provide the necessarycompressibility and flexibility in the radial direction by beingcomprised of a foamed material.

Preferably, the above-mentioned annular element is affixed to the ringprovided as a vibration damper so as to hold it in a defined position inthe neutral state. To this end, the annular element is either locked tothe ring in a form-fitting, detent fashion and/or preferably glued tothe ring or is vulcanized and/or injection molded onto it. Ideally, thering has form-fitting elements in the form of undercuts or raised areasinto or around which the material of the annular element flows so thatthe bond between the ring and the annular element encompassing it isensured by the form-fitting engagement and does not depend solely on aglued connection, which can come loose over time under the influence ofthe vibrations that the ring executes during operation.

FIGS. 5d and 5e show a second variant of the above-explained second,exemplary embodiment. All of the statements made above in connectionwith the second exemplary embodiment and its first modification apply tothis variant, provided that nothing to the contrary is stated in thefollowing explanation of the things that have been modified.

This second variant is distinguished by the fact that theabove-described annular element, which holds the ring so that it can actas a vibration damper during operation, is embodied as an elastic,preferably flexible or rubbery-elastic form-fitting element, which inthe installed state, fits snugly into a local recess, preferably on theouter circumference of the ring, and another local recess, preferably onthe inner circumference of the cavity—and thus holds the ring in itsproper neutral position, ideally solely by means of form-fitting andfrictional engagement. Ideally, the annular element is a single cord—orat least one cord—that is closed in the circumference direction,particularly in the form of a so-called O-ring, as is commonly used inthe art for sealing purposes and is therefore available “off the shelf”as an inexpensive standard element in an extremely wide variety ofthicknesses, diameters, and qualities.

FIGS. 6 through 9 show a third exemplary embodiment of the invention.

The mode of operation of this third exemplary embodiment of theinvention differs significantly from the first two exemplary embodimentsbecause in this case, the vibration-reducing component 7 is embodied ina significantly different way.

The basic design of the tool chuck, which in this case as well isdistinguished by the welding of a base body 2 to the sleeve part 3 or bythe one-piece embodiment produced by laser sintering or the like, does,however, correspond to that of the first two exemplary embodiments andtherefore statements made about them in this regard also apply here.

As shown in FIG. 6, in this exemplary embodiment as well, a cavitybegins in the region of this transition between the base body 2 and thesleeve part 3; this cavity extends in the direction of the axis ofrotation R to the tool holder 4 and protrudes a certain distance fartherinto the region of the securing flange 6, but does not reach into thecoupling section 5.

In this exemplary embodiment as well, the cavity is embodied asconspicuously short in the direction of the longitudinal axis; in thiscase, its length L_(K) is less than ⅖ the length L_(W) of the toolholder; it is clear that the cavity overlaps with the tool holder 7 fora certain distance in that it extends into the vicinity of the outlet ofthe tool holder.

A special feature in this exemplary embodiment, which is immediatelyapparent in FIG. 6, is the fact that the sleeve part 3 has a firstannular flange 11 and a second annular flange 12 on its end faceprovided for attachment to the base body 2. The first annular flange 11is used for connecting to the base body 2, preferably by means ofwelding. Only this annular flange 11 is used to transmit to the basebody 2 the torque that the machine tool exerts on the sleeve part 3. Thesecond annular flange 12 is accommodated concentrically inside the firstannular flange 11, but is not directly connected to the base body 2.Radial vibrations of the sleeve section 3 in the direction of the arrowRS therefore result in corresponding movements of the second annularflange 12. The vibration-reducing component 7 is fastened to the secondannular flange 12.

The vibration-reducing component 7 is embodied as a separate componentthat is independent of the base body 2 and sleeve part 3. It is fastenedto the second annular flange and, at its outer circumference, isfastened to the base body 2. In this case, the vibration-reducingcomponent 7 influences the vibration behavior of the annular flange 12significantly due to its mass and/or preferably also due to itsintrinsically existing elasticity that produces a certain naturalvibration behavior, which on the whole exerts a positive influence onthe vibration behavior of the overall system.

As can be seen in the figure, the vibration-reducing component 7 in thiscase is embodied as a spring and is therefore intrinsically able tovibrate; it is preferably made of a spring steel. In this exemplaryembodiment, the vibration-reducing component is composed of three rings14, 15, and 16, which are flexibly connected to one another by means ofbridge pieces 17. The innermost ring 14 is indirectly immobilizedrelative to the sleeve part 3 and the outside of the ring 16 isimmobilized, preferably directly, relative to the base body. With asuitable dimensioning of the bridge pieces 17, the two latter rings 15and 16 are able to vibrate relative to the ring 14.

In this exemplary embodiment, in order to influence the vibrationbehavior of the vibration-reducing component 7, it can be advantageousto fill the open spaces between the bridge pieces 17 with avibration-damping material, for example composed of plastic.

A modification of this exemplary embodiment not shown in the figures isdistinguished by the fact that the vibration-reducing component 7 inthis case is not an intrinsically vibrating spring element, but rather apreferably solid ring, ideally composed of a heavy metal. To this end,the second annular flange 12 is embodied as thin-walled so that duringoperation, the vibration-reducing component 7 that it holds can beexcited to execute vibrations—essentially in the radial direction—as aresult of its spring action. It is thus possible to implement avibration damper, which advantageously influences the vibration behaviorof the sleeve part 3.

Naturally there are also mixed forms possible, where thevibration-reducing component 7 vibrates partially within itself andexecutes partially vibrations as a whole unit on the thin-walled,flexibly embodied second annular flange.

All of the above-explained exemplary embodiments share the fact that itcan be advantageous to additionally fill the cavity with a liquid thatpositively influences the vibration behavior.

FIGS. 10 through 12 show a fourth exemplary embodiment of the invention.

This exemplary embodiment differs fundamentally from the exemplaryembodiments described above because in this case, the vibration-reducingcomponent is not an insert piece, but instead functions as a fastenerthat at least essentially lies completely within the flow of force andtorque and holds the base body 2 and the sleeve element 3 together.

In connection with this exemplary embodiment, the term “component” isused loosely here because the component does not ever have to have beena separate component, but can be a layer that is used to join the basebody 2 and the sleeve part 3. The vibration-reducing component 7 can,for example, be composed of a metal layer or of a correspondingly sturdyplastic layer that is used to cast, solder, or in the broadest sense,glue, the base body 2 and the sleeve part 3 to each other. If the layeris a metal layer, then it has turned out to be particularly advantageousto install a copper layer.

In any case, the thickness of the above-mentioned layer perpendicular tothe surfaces that are to be joined to each other is designed so that itproduces the desired damping behavior. There is no universally requiredformula for this, but the person skilled in the art can easily use therelevant experiments that are customary in the field to discover howthick the respective layer must be in order to demonstrate the desireddamping behavior.

It is advantageous to embody the end faces of the base body 2 and thesleeve part 3, which are joined with the aid of the above-mentionedlayer, as conical or circular so that the sleeve part 3 and the basebody 2 are pressed into one another in a centered fashion when advancingforces or corresponding reaction forces occur, which act in thedirection of the axis of rotation R of the tool chuck 1.

The surface of the end faces of the sleeve part 3 and/or the base body 2that are to be joined with the aid of the above-mentioned layer can alsoadvantageously be provided with undercuts or a profiling into which thematerial of the layer can penetrate, thus producing an anchoring throughform-fitting engagement and not solely through adhesion.

In addition, for the sake of completeness, the following should begenerally noted:

Protection is sought not only for the devices explained, butparticularly also for methods for producing such a device.

One of these methods is distinguished by the fact that the tool chuck 1is composed of two parts, namely

a base body, which constitutes the coupling section 5 for coupling tothe machine tool and constitutes the securing flange 6 for grasping andholding the chuck 1 during tool changes and

a sleeve part 3, which constitutes the tool holder 4.

At least one of these parts, on its end face oriented toward the jointhas a recess into which a vibration-reducing component 7 is inserted,preferably so that it is subsequently enclosed between the base body 2and the sleeve part 3. Then the base body and the sleeve part arejoined, possibly during exertion of forces in the direction of the axis,of rotation R, in order to prestress the vibration-reducing component inthe manner described at the beginning.

Protection is also sought for a design that is distinguished solely bymeans of the following features, to which other features from thedescription can be optionally added:

A tool chuck 1, which is distinguished by the fact that avibration-reducing component 7, which is preferably embodied as aseparate spring element, is held inside the tool chuck and embodied sothat during operation, the vibration-reducing component 7 is excited toresiliently execute intrinsic vibrations so that during operation, apart of the spring element that protrudes freely into the cavity of thetool chuck begins to vibrate relative to the part of the spring elementthat is fastened to the tool chuck.

Furthermore, independent protection is also claimed for the followingdesign, whose features can be optionally supplemented with one or morefeatures horn the description:

A tool chuck, whose interior is equipped with a vibration-reducingelement in the form of a preferably metal disc or a preferably metalcylinder, which rests with its end faces directly against thecorresponding end faces of the sleeve part, and base body and ispreferably embodied so that it is permanently prestressed in elasticfashion between them. In a preferred modification of this, the disc orthe cylinder rests against the surfaces of the sleeve part and/or thebase body on all sides, without the interposition of a plastic orelastomer layer.

Independent protection is also claimed for the following design, whosefeatures can optionally be supplemented with one or more features fromthe description:

A tool chuck for clamping a tool in a machine tool, having a base body 2and a sleeve part protruding therefrom 3, which sleeve part forms a toolholder 4 for fixing a tool shaft in a frictional, nonpositive fashion; acavity is provided in the tool chuck and accommodates avibration-reducing liquid; preferably, the cavity begins in the vicinityof the transition from the base body 2 to the sleeve part 3, extendsalong the axis of rotation R in the direction toward the tool holder 4,and in the direction along the axis of rotation R. has a length L_(K)that is less than ⅖ and preferably less than ⅕ the length L_(W) of thetool holder 4 in this direction and ideally, the liquid is introducedinto the cavity via an opening, which is then closed by a screwed-in orpressed-in or welded sealing element; a screwed-in sealing element whosescrew-in depth can be used to set the pressure of the liquid in thecavity or a pressed-in sealing element whose press-in depth can be usedto set the pressure of the liquid in the cavity are clearly preferable.

With regard to all of the embodiments described here, it should be notedthat the cavity and the vibration-reducing component are preferablymatched to each other so that the vibration-reducing component occupiesthe preponderance and better still, at least 70%—of the volume of thecavity. Ideally, the vibration-reducing component essentially fills theentire cavity.

The vibration-reducing component can have a preferably central throughopening that preferably itself serves directly as a conduit for coolantthat is supplied to the tool through the interior of the chuck.

The maximum inner radius of the cavity is preferably greater than themaximum dimension of the cavity in the direction of the axis of rotationR.

1. A tool chuck for clamping a tool in a machine tool, the tool chuckcomprising: a base body; a sleeve part protruding from the base body andforming a tool holder for fixing a tool shaft in a frictional,nonpositive fashion; and a cavity in the tool Chuck in which avibration-reducing component is accommodated.
 2. The tool chuckaccording to claim 1, wherein the cavity begins in a vicinity of atransition from the base body to the sleeve part, extends along an axisof rotation in a direction of the tool holder, and in the directionalong the axis of rotation has a length that is less than ⅖ a length ofthe tool holder in this direction.
 3. The tool chuck according to claim1, wherein a length of the tool holder embodied in the sleeve part makesup more than ¾ of an overall length of the sleeve part.
 4. The toolchuck according to claim is wherein the cavity directly adjoins a regionof change in diameter at which the sleeve part transitions into the basebody or lies within this region so that the change in diameter occurs ina vicinity of a circumference wall delimiting the cavity.
 5. The toolchuck according to claim 4, wherein the cavity is encompassed in acircumference direction b a joint between the base body and the sleevepart, which joint is embodied in the form of a welded seam.
 6. The toolchuck according to claim 1, wherein the vibration-reducing component isa solid, metal, annular disc with a central opening, with a maximumdimension (B_(max)) of the disc parallel to an axis of rotation beingless than a maximum diameter (D_(max)) of the disc, in accordance withthe equation B_(max)/D_(max)≦2.
 7. The tool chuck according to claim 6,wherein the disc is made of a heavy metal or of a material that containsa heavy metal.
 8. The tool chuck according to claim 6, wherein the discrests with a circumference surface directly against a correspondingcircumference surface of the sleeve part and/or base body.
 9. The toolchuck according to claim 6, wherein the disc is secured in anelastically prestressed fashion with its end faces between correspondingend faces of the sleeve part and the base body.
 10. The tool chuckaccording to claim 6, wherein the disc rests with a circumferencesurface against a corresponding circumference surface of the sleeve partand/or the base body via an intermediate layer composed of plasticand/or elastomer so that with proper operation, the disc is able toexecute relative movements in a radial direction in relation to thesleeve part and the base body, and the end faces of the disc contact thecorresponding end faces of the sleeve part and base body only in such away that the disc is not immobilized by friction occurring there. 11.The tool chuck according to claim 1, wherein the vibration-reducingcomponent is a spring element that is secured inside the tool chuck andis embodied in such a way that it the spring element is excited toexecute intrinsic vibrations during operation—so that during operation,a part of the spring element that protrudes freely into the cavity ofthe tool chuck begins to vibrate relative to a part of the springelement that is fastened to the tool chuck.
 12. The tool chuck accordingto claim 11, wherein the sleeve part, on its end face oriented towardthe base body, has a first annular flange for connection to the basebody and a second flange, which is situated concentrically inside thefirst annular flange and, even in an installed state, does not directlycontact the base body, against which second flange the spring elementrests, while a section of the spring element that is oriented away froma fastening point protrudes into the cavity in a way that allows thesection of the spring element to vibrate freely.
 13. The tool chuckaccording to claim 11, wherein the spring element is composed of atleast two rings situated one inside the other, which are connected toone another by bridge pieces.
 14. The tool chuck according to claim 1,wherein the base body and the sleeve part are separate components thatare joined to each other in a frictional, nonpositive fashion notdirectly, but with an interposition of a damping material layer, and awedge-shaped or conical gap is situated between the sleeve part and thebase body and is filled with the layer of damping material.
 15. A toolchuck for clamping a tool in a machine tool, having, the tool chuckcomprising: a base body; and a sleeve part protruding from the base bodyand forming a tool holder for fixing a tool shaft in a frictional,nonpositive fashion; wherein the base body and the sleeve part areseparate components that are joined to each other in a frictional,nonpositive fashion not directly, but with an interposition of a dampingmaterial layer, and a wedge-shaped or conical gap is situated betweenthe sleeve part and the base body and is filled with the layer ofdamping material.
 16. The tool chuck according to claim 15, wherein endfaces of the sleeve part and/or the base body that form the gap haveundercuts into which the damping material layer penetrates and producesa form-fitting engagement.